1. Field of the Invention
The present invention relates to novel crystalline forms of a 3-(sulfonyl-1-phenoxyethyl)pyrrolidine compound, which has activity as a serotonin (5-HT) reuptake inhibitor and, in one embodiment, has the characteristic of being selectively restricted from the central nervous system. The invention also relates to pharmaceutical compositions comprising such compounds, processes, and intermediates for preparing such compounds and methods of using such compounds to treat pulmonary arterial hypertension and other ailments.
2. State of the Art
U.S. Patent Application Publication No. 2012/0088799 to Stangeland et al. discloses novel compounds that have activity as a serotonin (5-HT) reuptake inhibitors, the disclosure of which is incorporated herein by reference. In particular, the compound, (S)-3-[(S)-2-methanesulfonyl-1-(4-trifluoromethyl-phenoxy)ethyl]pyrrolidine is specifically disclosed in this application.
The chemical structure of (S)-3-[(S)-2-methanesulfonyl-1-(4-trifluoromethyl-phenoxy)ethyl]pyrrolidine is represented by formula I:

When preparing compounds for long term storage and when preparing pharmaceutical compositions and formulations, it is often desirable to have a crystalline form of the therapeutic agent that is neither hygroscopic nor deliquescent. It is also advantageous to have a crystalline form that has a relatively high melting point (i.e. greater than about 150° C.), which allows the material to be processed, for example, micronized, without significant decomposition. Accordingly, a need exists for a stable, non-deliquescent form of (S)-3-[(S)-2-methanesulfonyl-1-(4-trifluoromethylphenoxy)ethyl]-pyrrolidine which has an acceptable level of hygroscopicity and a relatively high melting point.